The floors and walls of enclosed chambers used for high temperatures such as hearths, kilns, burners, boilers, fireboxes, and crematoriums are often comprised of refractory material as they have direct exposure to heat and flame. Refractory material refers to material capable of enduring high temperatures and includes concrete, firebricks, mortars, castables and ceramic fibers. Hearths, kilns, burners, boilers, fireboxes, crematoriums, and citrus dryers or incinerators are such chambers in which substances are heated or burned resulting in ash, slag, or debris which require collection. The proper removal of these substances is critical for a multitude of reasons and is dependent on the purpose and use of the chambers. For example, proper removal of the ashes following a cremation has both legal and ethical concerns at hand. In the case of crematoriums, best practice and regulation requires that the cremains following each separate cremation be removed and recovered nearly 100% in the hope that the cremains of one cadaver not be mixed with the cremains of a successive cadaver.
Damage to and erosion of the heath can be attributed to a number of reasons including chemical reactivity and physical wear. Refractory linings are subject to regular wear from the scraping or brushing of metal brushes or other tools on the furnace walls or by scraping and bumping during loading. In theory, refractory wear should be uniform, but in practice this does not occur as most often, the refractory surface is composed of modules of refractory material. The most intense wear occurs at the slag/metal interface, where sidewalls join the floor, and at thin spots caused by poor lining installation. Visible hot spots on the exterior metal of any cremator, kiln or furnace are an indication of a refractory issue. Breech of the refractory linings can damage the machinery of the equipment requiring costly repairs or even replacement.
In some cases, the correct method of removing what results from the use of a heating chamber such as an incinerator, furnace or even a crematorium is vital to allow proper functioning and to avoid damage of the equipment. In animal cremators and incinerators, calcium buildup can occur on the surface of the chamber's hearth floor. This accumulation can be cleared from the floor surface occasionally, however if calcium build up remains unchecked, the severe buildup of the mineral can result in unevening of the crematorium floor level, causing grease to leak out of the chamber. In the instance of incinerators, the deposition of slag can be detrimental to the equipment. Slag results when low grade or organic waste materials are used in a combustion process. The term is also used to refer to the byproduct of steelmaking Handling slag deposits is an important factor in controlling the design and operation of high volume processing municipal incinerators. Slag not only adheres to but often also penetrates through and reacts chemically with the refractory material. Over time, its accumulation alters the normal heat flow and congests gas passages resulting in the cracking of refractory modules on the chamber surface and in the interior of the chamber wall. Similarly, citrus peel dryers process waste membrane and peels of pre-processed citrus fruit for the production of citrus pulp pellets to be used as agricultural animal feed. The process results in sharp debris which cuts into the refractory surface of the dryer. Further, acid from the peels erode the chamber surface as well. Lastly, joints, cracks and depressions within high heat chambers which are constructed with modules of refractory material become a place of collection for the debris, by product and cremains, in the case of crematoriums.
Additionally, the resulting dust and ash can, in some instances, affect the efficiency of the equipment. Furnaces are such an example of heat chambers whose neglected maintenance and cleaning can affect the efficiency of the system. Furnaces are a major source of heat production in many parts of the world. The system works by drawing in cold air which is passed through a filter and subsequently heated, sent through a flue and into the duct network of the building. The heavy presence of dirt in the system results in a less efficient furnace as more fuel is required to be burned to produce the same amount of heat. Further, dust, mold, and other allergen contaminants accumulate in the furnace and travel with the heated air into the building where it is breathed in by its occupants.
Proper upkeep of these high heat chambers can require removal of nearly all debris and by products left in the system floor and on its walls. Removing loose soot and debris from the fireside portion of a boiler often involves scrubbing with a wire brush and power vacuuming, whereas water is used to flush the waterside portion of a boiler. Following a cremation, in another example, the cremains are most commonly crudely removed by a blunt ended shovel or hoe, a steel tipped rake or an ordinary broom. Regular vacuums are often used to clean through furnaces. In the case of industrial plants in the chemical and building materials industries, protocols require that the release of particulate into the environment be reduced. Hence, the industry commonly uses wet particulate dust scrubbers to trap particulates and pull them from the gas stream by injecting a liquid, often water, into the waste gas stream and collecting the liquid droplets which impact and entrain the solid matter from the stream and into the sump.
There are various ways refractory materials are placed in incinerators and similar chambers to construct them. In some instances the refractory material can be poured and hardened to a consistency of concrete. Other systems use insulating firebricks for the ceilings whereas older systems utilize ceramic fiber module ceilings. Each module of ceramic fiber contains hardware used to secure the module to the ceiling. Metal studs can then used to secure the module and weld its associated hardware to a metal sheet on the ceiling. Some cremators have a hearth floor consisting of castable tiles which is replaced by pouring a smooth castable floor which is easier to sweep out the cremains. The chamber side walls always consist of firebricks. Refractory insulating materials are also installed behind the cremation chamber side wall to keep an excessive amount of heat from radiating to the exterior of the cremator.
The afterburner chamber walls are often located on the back section of the cremation chamber side wall of certain models. They are defined by an opening, the gas pass window, through which the gases from the main cremation chamber pass and where an afterburner incinerates the pollutants to produce clean air emissions out of the stack. This additional incineration also adds to the buildup of debris which is required to be removed. As described above, the refractory components of such a high heat chamber are most often of a modular nature and require piecewise construction and repair, and hence have joints between the bricks or tiles. The presence of joints together with the wearable refractory material makes the interior chamber susceptible to damage if not emptied properly or with the appropriate equipment.
Individual modules can also be replaced as they wear out however, over time with routine use and wear, the entire ceramic module ceiling or firebrick flooring requires replacement. Retorts in crematories are out of operation about five days per year due to maintenance or repairs. The average cost to re-brick a system in today's market can be $20,000 or more. It is expected that 8000 hours of operation can be performed prior to complete re-bricking if proper wear and tear is exerted on the retort. Exhaust gases from the cremation process can range from 500 to 1000 degrees F. Temperatures can reach 2000 degrees in the instances of large case load and malfunction. To protect against a fire, a refractory lining of sufficient thickness and insulating capabilities is used. The refractory life of the lined stack also requires replacement over time.
An alternative to the commonly used methods and devices for clearing and cleaning such chambers would be the extended sweep. The extended sweep provides a versatile design which allows a vacuum, power washer, or air blower to reach narrow and deep spaces to remove debris with gentle but effective force with minimal damage to the refractory material of the chamber. The thin long neck of the device allows for easy control and access to lengthy chambers or tunnels. The manifold at the front end of the device can be customized to fit the surfaces to be cleared. The air vents on the manifold allow for air flow inward or outward. Multiple streams of air flow will allow for removal of debris from the joints between the refractory material modules and seams between the side wall and the hearth floor or ceiling. The unique design of the extended sweep allows the device to be taken apart into portions which can be easily stored and shipped. It also is designed to not allow virtually any debris or ash to collect in portions of the device. The wheels sit loosely in between the pins on the manifold. The diameter of the wheel's open center is larger than the diameter of the manifold column giving the wheels to move against or away from the manifold independently of each other hence allowing fluid movement over uneven terrain. The extended sweep device effectively extends to difficult to reach areas and clears the surface desired in less time and in a less labor intensive manner.